The present invention relates generally to electric machines and, more particularly, to a spacer for electrically insulating various conductors forming a winding arrangement in a stator assembly of an electric machine.
Electric machines may be used for a variety of applications, including in connection with automobile power trains. For example, a conventional automobile may use an electric machine as a starting motor for an internal combustion engine, or as an alternator to generate electricity and deliver power to vehicle accessories and/or charge a vehicle's battery.
An illustrative electric machine includes a rotor and a stator. The stator is comprised of a stator stack or core and a plurality of electrical conductors, or windings, that are inserted into the stator stack. The windings are interconnected (e.g., welded together) at weld-end turns or joints in order to form a circuit that is necessary for operation of the electric machine. In particular, the electric machine operates when the stator interacts with the rotor through magnetic fields to convert electric energy to mechanical energy, or to convert mechanical energy to electrical energy.
The conductors may form a multi-phase electric machine. Each phase interconnects to the other phases in order to complete a full circuit. The conductors are electrically insulated from each other to insure that the motor does not short. A common concern with motor fabrication is possible damage to the conductors during the manufacturing process. This may be caused by bends and twists formed in the conductor so that the routing within the stator is optimized. Depending upon the dimensions and configuration of the stator, the bends and twists may be extreme. More particularly, damage may occur in the insulation supported on the outer surface of the conductors.
The present disclosure relates to a spacer for supporting conductors in the stator assembly of an electric machine, the spacer including an insulating body formed of an electrically non-conductive material. A first surface is supported by the insulating body and faces axially inwardly for contacting a plurality of short electrical conductors of an inner winding set. A second surface is supported by the insulating body and is positioned radially inwardly from the first surface and faces axially inwardly for contacting a plurality of short electrical conductors of an outer winding set. A crossover pocket is supported by the insulating body and extends radially intermediate the first surface and the second surface, and faces axially inwardly for receiving an electrical conductor defining a crossover conductor to electrically connect the inner winding set and the outer winding set. A phase lead pocket is supported by the insulating body and faces axially outwardly for receiving a terminal phase lead conductor.
According to a further illustrative embodiment of the present disclosure, an electric machine includes a stator core including a sidewall extending about a longitudinal axis. An inner winding set is supported by the stator core and includes a plurality of common electrical conductors and a plurality of short electrical conductors. The first winding set is a multi-phase winding provided in a first conductor layer and a second conductor layer positioned radially outwardly from the first conductor layer. An outer winding set is supported by the stator core and is positioned radially outwardly from the inner winding set and includes a plurality of common electrical conductors and a plurality of short electrical conductors. The second winding set is a multi-phase winding provided in a third conductor layer and a fourth conductor layer positioned radially outwardly from the third conductor layer. A plurality of crossover conductors is supported by the stator core for electrically connecting the inner winding set and the outer winding set. A plurality of terminal phase lead conductors are supported by the stator core, each terminal phase lead conductor electrically coupled to one of the phases of the inner and outer winding sets. A spacer includes an insulating body formed of a non-conductive material, the spacer positioned axially outwardly from the stator core and including a plurality of positioning elements cooperating with short electrical conductors of the inner and outer winding sets, with the common electrical conductors of the inner and outer winding sets, with the plurality of crossover conductors, and with the terminal phase lead conductors.
According to another illustrative embodiment of the present disclosure, a method of forming a stator assembly of an electric machine includes the steps of providing a stator core having an insertion end and an opposing end, placing a plurality of common electrical conductors within slots of the stator core, placing a plurality of short electrical conductors within slots of the stator core, placing a plurality of crossover conductors within slots of the stator core, and positioning a spacer proximate the insertion end of the stator core. The method further includes the steps of aligning a first surface of the spacer with the short electrical conductors, aligning crossover pockets with the crossover conductors, and moving the spacer toward the insertion end of the stator core such that the short electrical conductors engage the first surface and are pushed into the slots of the stator core, and the crossover conductors are received within the crossover pockets of the spacer.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.